The present application claims priority to Japanese Application(s) No(s). P2000-301404 filed Sep. 29, 2000, which application(s) is/are incorporated herein by, reference to the extent permitted by law.
1. Field of the Invention
The present invention relates to an IC card and method for fabricating such an IC card, and in particular, the present invention relates to a non-contacting type IC card having an uneven surface made of a plurality of small grooves for degassing air.
2. Description of the Related Art
Conventionally, personal ID (IDentification) cards for identifying individuals carrying data based on a magnetic or an optical method have been widely used as a credit card and the like. However, as the ID cards become popular, tampered data and forged cards are circulating frequently, and thereby actually increasing the number of persons who suffered damages or the like due to such forged cards, and thus raising social problems with respect to the security of personal information. Therefore, recently, an IC (Integrated Circuit) card carrying a built-in IC chip is drawing attention as suitable for personal data management, because the IC card can store a larger capacity of information and cryptographic data.
Such a conventional IC card has usually electrically connectable mechanical connection terminals for data exchange between a built-in IC circuit thereof and an external data processing unit. Therefore, there have been various problems such as securing of a hermetic seal of the IC circuit, a countermeasure against electrostatic destruction, a deficient contact between terminal electrodes, a complicated mechanism of a read/write apparatus and the like. Further, as manual handling of the IC card by the user to insert into the card read/write apparatus is required in any case, thus such operations. are decreased in efficiency and simplicity thereof depending on a certain filed of application. Therefore, a realization of a non-contacting type IC card has been expected for a long time. The non-contacting type IC card can be used in a portable state without the need of complex manual handling and is capable of exchanging data with a remotely located data processing unit.
Hence, such non-contacting type IC card having an antenna for handling electromagnetic waves and an IC chip incorporating a memory and an arithmetic function are developed in a card shape made of plastic. This IC card is intended to be used by driving its IC chip with an induced electromotive power that is induced in the antenna installed within the card, and energized by an external electromagnetic wave supplied from an external reader/writer apparatus. Accordingly, this type of card does not require any mechanical contacts to be connected to the external device. Further, no battery is required in the card, thereby providing an excellent card having superiority in activity. The necessity of such non-contacting type IC cards having visible identification display function and security control function by encrypted electronic information is increasing more and more.
As indicated in FIGS. 26 and 27, this type of IC card 100 is manufactured by sandwiching a substrate 101 having an IC chip mounted thereon between a pair of protective covering members 102a and 102b, and bonding and sealing the same, for example, with a thermoplastic adhesive or the like. However, because the conventional bonding process using thermoplastic adhesives is performed by directly applying the adhesives on the protective covering members 102a and 102b, a vacuum degassing of air between the substrate 101 and the protective covering members 102a, 102b could not be well controlled. Therefore, pneumatic foams 103 are apt to be generated and remained, for example, between the substrate 101 and the protective covering members 102a or 102b as shown in FIG. 26. As a result, there exist swellings 104 on the surfaces of the IC card 100 due to the pneumatic foams 103 as shown in FIG. 27. This results in serious defects and problems in the quality of the IC card 100.
Conventionally, it is provided a lamination process of IC card component members provided on sheets each cut in a so-called page size (A3 size) on which 18 pieces of IC cards are simultaneously assembled. In this case, in order to prevent the occurrence of such pneumatic foams 103, a vacuum degassing process is applied for degassing air from four corners thereof after the lamination process for approximately 60 to 120 seconds, but this substantially lowers the productivity of the IC cards. Furthermore, even after the vacuum degassing process of the lamination collated members, some pneumatic foams tend to remain partially between the lamination members. This has resulted in a plurality of swells on the surface of the IC card after a hot press lamination bonding, thereby lowering the productivity down to 20 to 50%.
Conventionally, an adhesive sheet that is a thermoplastic adhesive or a thermoplastic resin sheet used for lamination and bonding between an antenna substrate and protective covering members made of, for example, a resin sheet are manufactured by a general-purpose film forming apparatus, and most of them are flat adhesive sheets with smooth surfaces. When this flat adhesive sheet is used, the pneumatic foams tend to be generated between the lamination component members. In particular, the softer the adhesive sheet is, the more sagging the sheet portions to be laminated become, thereby causing a plurality of the pneumatic foams being formed in the sagging portions of the lamination and between a plurality of the lamination members. Accordingly, after the card lamination bonding, the sagging portions result in a plurality of partial swellings on the IC card surface to cause problems and defects.
The present invention has been contemplated to solve the above-mentioned problem associated with the prior art, and a feature of the invention is to provide an IC card carrying no swelling on the card surface resulting from the pneumatic foam.
According to the present invention, the IC card is an integrated circuit mounted card that has an IC chip and an antenna circuit on a substrate, and the substrate is interposed between at least a pair of films having an uneven pattern made of small grooves for degassing air.
In the IC card according to the invention as described above, because of the providing the uneven pattern made of small grooves formed at least on one surface of each of the pair of the films opposing the substrate, residual air remaining between the substrate and the films is caused to be discharged to the outside through this uneven pattern made of small grooves upon fabrication the IC card.
In the method for fabricating the IC card of the present invention, uneven patterns made of small grooves are formed on a pair of films to be attached to both surfaces of a card substrate, so that air residing between the substrate and the films are degassed to outside through these grooves.